1. Field of the Invention:
This invention relates to a computer, and more particularly to an input unit, such as a mouse, adapted to be connected to a computer or a keyboard, for generating a predetermined pulse signal.
2. Description of the Related Art:
Heretofore, a mouse is well known as an input unit for generating a pulse signal, to execute a desired command, to a computer by the operator's operation from outside, for example.
In use, the mouse is connected to the computer or a keyboard for outputting a predetermined count number of pulse signals according to an amount of movement of the mouse in four directions therearound. In this kind of mouse, the count number of pulses per inch and speed are predetermined, i.e., 100 to 200 pulses are generated with respect to the movement of 15 to 30 cm in ordinary use.
This kind of mouse is used in setting procedure items on the display screen and graphic display, for example. Specifically, in setting a procedure item, the mouse body is moved to move the cursor to a desired item selected among a plurality of procedure items appeared on the display screen, and then a switch mounted on the mouse is operated while the cursor is in a desired position. In drawing a graphic by dots on the display screen, the operator keeps watching on the screen and moves the mouse body to describe a desired line on the screen.
According to this kind of mouse, some particular procedures can be executed by moving the mouse body while watching the display screen, without using a special keyboard having many operating keys. Therefore it can be operated easily even by any unexperienced operator.
However, with this conventional mouse, if the number of items to be selected is increased or if a graphic to be described is complex, an adequate space is necessary for moving the mouse body with some play, thus increasing a required amount of movement of the mouse body, which creates an excessive labor to be done by the operator and hence lowers the working efficiency.
Consequently, for minimizing the operator's labor and hence improving the working efficiency, the count number of pulses to be outputted from the mouse must be increased to about 400, for example; this is, the amount of movement of the mouse body must be reduced to 4 to 5 cm, which is equivalent to that number.
Yet if the count number of pulses to be outputted from the mouse is so increased, the mouse reacts sensitively for its own slight movement so that the mouse body must be moved slowly to describe a delicate or sophisticated graphic carefully on the display screen, which is laborious and time-consuming. This conventional mouse is therefore not suitable for delicate or sophisticated work.